1 /*
2 * GUSEMU32 - mixing engine (similar to Interwave GF1 compatibility)
3 *
4 * Copyright (C) 2000-2007 Tibor "TS" Schütz
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24
25 #include "qemu/osdep.h"
26 #include "gusemu.h"
27 #include "gustate.h"
28
29 #define GUSregb(position) (* (gusptr+(position)))
30 #define GUSregw(position) (*(uint16_t *) (gusptr+(position)))
31 #define GUSregd(position) (*(uint32_t *)(gusptr + (position)))
32
33 #define GUSvoice(position) (*(uint16_t *)(voiceptr+(position)))
34
35 /* samples are always 16bit stereo (4 bytes each, first right then left interleaved) */
gus_mixvoices(GUSEmuState * state,unsigned int playback_freq,unsigned int numsamples,int16_t * bufferpos)36 void gus_mixvoices(GUSEmuState * state, unsigned int playback_freq, unsigned int numsamples,
37 int16_t *bufferpos)
38 {
39 /* note that byte registers are stored in the upper half of each voice register! */
40 uint8_t *gusptr;
41 int Voice;
42 uint16_t *voiceptr;
43
44 unsigned int count;
45 for (count = 0; count < numsamples * 2; count++)
46 *(bufferpos + count) = 0; /* clear */
47
48 gusptr = state->gusdatapos;
49 voiceptr = (uint16_t *) gusptr;
50 if (!(GUSregb(GUS4cReset) & 0x01)) /* reset flag active? */
51 return;
52
53 for (Voice = 0; Voice <= (GUSregb(NumVoices) & 31); Voice++)
54 {
55 if (GUSvoice(wVSRControl) & 0x200)
56 GUSvoice(wVSRControl) |= 0x100; /* voice stop request */
57 if (GUSvoice(wVSRVolRampControl) & 0x200)
58 GUSvoice(wVSRVolRampControl) |= 0x100; /* Volume ramp stop request */
59 if (!(GUSvoice(wVSRControl) & GUSvoice(wVSRVolRampControl) & 0x100)) /* neither voice nor volume calculation active - save some time here ;) */
60 {
61 unsigned int sample;
62
63 unsigned int LoopStart = (GUSvoice(wVSRLoopStartHi) << 16) | GUSvoice(wVSRLoopStartLo); /* 23.9 format */
64 unsigned int LoopEnd = (GUSvoice(wVSRLoopEndHi) << 16) | GUSvoice(wVSRLoopEndLo); /* 23.9 format */
65 unsigned int CurrPos = (GUSvoice(wVSRCurrPosHi) << 16) | GUSvoice(wVSRCurrPosLo); /* 23.9 format */
66 int VoiceIncrement = ((((unsigned long) GUSvoice(wVSRFreq) * 44100) / playback_freq) * (14 >> 1)) /
67 ((GUSregb(NumVoices) & 31) + 1); /* 6.10 increment/frame to 23.9 increment/sample */
68
69 int PanningPos = (GUSvoice(wVSRPanning) >> 8) & 0xf;
70
71 unsigned int Volume32 = 32 * GUSvoice(wVSRCurrVol); /* 32 times larger than original gus for maintaining precision while ramping */
72 unsigned int StartVol32 = (GUSvoice(wVSRVolRampStartVol) & 0xff00) * 32;
73 unsigned int EndVol32 = (GUSvoice(wVSRVolRampEndVol) & 0xff00) * 32;
74 int VolumeIncrement32 = (32 * 16 * (GUSvoice(wVSRVolRampRate) & 0x3f00) >> 8) >> ((((GUSvoice(wVSRVolRampRate) & 0xc000) >> 8) >> 6) * 3); /* including 1/8/64/512 volume speed divisor */
75 VolumeIncrement32 = (((VolumeIncrement32 * 44100 / 2) / playback_freq) * 14) / ((GUSregb(NumVoices) & 31) + 1); /* adjust ramping speed to playback speed */
76
77 if (GUSvoice(wVSRControl) & 0x4000)
78 VoiceIncrement = -VoiceIncrement; /* reverse playback */
79 if (GUSvoice(wVSRVolRampControl) & 0x4000)
80 VolumeIncrement32 = -VolumeIncrement32; /* reverse ramping */
81
82 for (sample = 0; sample < numsamples; sample++)
83 {
84 int sample1, sample2, Volume;
85 if (GUSvoice(wVSRControl) & 0x400) /* 16bit */
86 {
87 int offset = ((CurrPos >> 9) & 0xc0000) + (((CurrPos >> 9) & 0x1ffff) << 1);
88 int8_t *adr;
89 adr = (int8_t *) state->himemaddr + offset;
90 sample1 = (*adr & 0xff) + (*(adr + 1) * 256);
91 sample2 = (*(adr + 2) & 0xff) + (*(adr + 2 + 1) * 256);
92 }
93 else /* 8bit */
94 {
95 int offset = (CurrPos >> 9) & 0xfffff;
96 int8_t *adr;
97 adr = (int8_t *) state->himemaddr + offset;
98 sample1 = (*adr) * 256;
99 sample2 = (*(adr + 1)) * 256;
100 }
101
102 Volume = ((((Volume32 >> (4 + 5)) & 0xff) + 256) << (Volume32 >> ((4 + 8) + 5))) / 512; /* semi-logarithmic volume, +5 due to additional precision */
103 sample1 = (((sample1 * Volume) >> 16) * (512 - (CurrPos % 512))) / 512;
104 sample2 = (((sample2 * Volume) >> 16) * (CurrPos % 512)) / 512;
105 sample1 += sample2;
106
107 if (!(GUSvoice(wVSRVolRampControl) & 0x100))
108 {
109 Volume32 += VolumeIncrement32;
110 if ((GUSvoice(wVSRVolRampControl) & 0x4000) ? (Volume32 <= StartVol32) : (Volume32 >= EndVol32)) /* ramp up boundary cross */
111 {
112 if (GUSvoice(wVSRVolRampControl) & 0x2000)
113 GUSvoice(wVSRVolRampControl) |= 0x8000; /* volramp IRQ enabled? -> IRQ wait flag */
114 if (GUSvoice(wVSRVolRampControl) & 0x800) /* loop enabled */
115 {
116 if (GUSvoice(wVSRVolRampControl) & 0x1000) /* bidir. loop */
117 {
118 GUSvoice(wVSRVolRampControl) ^= 0x4000; /* toggle dir */
119 VolumeIncrement32 = -VolumeIncrement32;
120 }
121 else
122 Volume32 = (GUSvoice(wVSRVolRampControl) & 0x4000) ? EndVol32 : StartVol32; /* unidir. loop ramp */
123 }
124 else
125 {
126 GUSvoice(wVSRVolRampControl) |= 0x100;
127 Volume32 =
128 (GUSvoice(wVSRVolRampControl) & 0x4000) ? StartVol32 : EndVol32;
129 }
130 }
131 }
132 if ((GUSvoice(wVSRVolRampControl) & 0xa000) == 0xa000) /* volramp IRQ set and enabled? */
133 {
134 GUSregd(voicevolrampirq) |= 1 << Voice; /* set irq slot */
135 }
136 else
137 {
138 GUSregd(voicevolrampirq) &= (~(1 << Voice)); /* clear irq slot */
139 GUSvoice(wVSRVolRampControl) &= 0x7f00;
140 }
141
142 if (!(GUSvoice(wVSRControl) & 0x100))
143 {
144 CurrPos += VoiceIncrement;
145 if ((GUSvoice(wVSRControl) & 0x4000) ? (CurrPos <= LoopStart) : (CurrPos >= LoopEnd)) /* playback boundary cross */
146 {
147 if (GUSvoice(wVSRControl) & 0x2000)
148 GUSvoice(wVSRControl) |= 0x8000; /* voice IRQ enabled -> IRQ wait flag */
149 if (GUSvoice(wVSRControl) & 0x800) /* loop enabled */
150 {
151 if (GUSvoice(wVSRControl) & 0x1000) /* pingpong loop */
152 {
153 GUSvoice(wVSRControl) ^= 0x4000; /* toggle dir */
154 VoiceIncrement = -VoiceIncrement;
155 }
156 else
157 CurrPos = (GUSvoice(wVSRControl) & 0x4000) ? LoopEnd : LoopStart; /* unidir. loop */
158 }
159 else if (!(GUSvoice(wVSRVolRampControl) & 0x400))
160 GUSvoice(wVSRControl) |= 0x100; /* loop disabled, rollover check */
161 }
162 }
163 if ((GUSvoice(wVSRControl) & 0xa000) == 0xa000) /* wavetable IRQ set and enabled? */
164 {
165 GUSregd(voicewavetableirq) |= 1 << Voice; /* set irq slot */
166 }
167 else
168 {
169 GUSregd(voicewavetableirq) &= (~(1 << Voice)); /* clear irq slot */
170 GUSvoice(wVSRControl) &= 0x7f00;
171 }
172
173 /* mix samples into buffer */
174 *(bufferpos + 2 * sample) += (int16_t) ((sample1 * PanningPos) >> 4); /* right */
175 *(bufferpos + 2 * sample + 1) += (int16_t) ((sample1 * (15 - PanningPos)) >> 4); /* left */
176 }
177 /* write back voice and volume */
178 GUSvoice(wVSRCurrVol) = Volume32 / 32;
179 GUSvoice(wVSRCurrPosHi) = CurrPos >> 16;
180 GUSvoice(wVSRCurrPosLo) = CurrPos & 0xffff;
181 }
182 voiceptr += 16; /* next voice */
183 }
184 }
185
gus_irqgen(GUSEmuState * state,unsigned int elapsed_time)186 void gus_irqgen(GUSEmuState * state, unsigned int elapsed_time)
187 /* time given in microseconds */
188 {
189 int requestedIRQs = 0;
190 uint8_t *gusptr;
191 gusptr = state->gusdatapos;
192 if (GUSregb(TimerDataReg2x9) & 1) /* start timer 1 (80us decrement rate) */
193 {
194 unsigned int timer1fraction = state->timer1fraction;
195 int newtimerirqs;
196 newtimerirqs = (elapsed_time + timer1fraction) / (80 * (256 - GUSregb(GUS46Counter1)));
197 state->timer1fraction = (elapsed_time + timer1fraction) % (80 * (256 - GUSregb(GUS46Counter1)));
198 if (newtimerirqs)
199 {
200 if (!(GUSregb(TimerDataReg2x9) & 0x40))
201 GUSregb(TimerStatus2x8) |= 0xc0; /* maskable bits */
202 if (GUSregb(GUS45TimerCtrl) & 4) /* timer1 irq enable */
203 {
204 GUSregb(TimerStatus2x8) |= 4; /* nonmaskable bit */
205 GUSregb(IRQStatReg2x6) |= 4; /* timer 1 irq pending */
206 GUSregw(TimerIRQs) += newtimerirqs;
207 requestedIRQs += newtimerirqs;
208 }
209 }
210 }
211 if (GUSregb(TimerDataReg2x9) & 2) /* start timer 2 (320us decrement rate) */
212 {
213 unsigned int timer2fraction = state->timer2fraction;
214 int newtimerirqs;
215 newtimerirqs = (elapsed_time + timer2fraction) / (320 * (256 - GUSregb(GUS47Counter2)));
216 state->timer2fraction = (elapsed_time + timer2fraction) % (320 * (256 - GUSregb(GUS47Counter2)));
217 if (newtimerirqs)
218 {
219 if (!(GUSregb(TimerDataReg2x9) & 0x20))
220 GUSregb(TimerStatus2x8) |= 0xa0; /* maskable bits */
221 if (GUSregb(GUS45TimerCtrl) & 8) /* timer2 irq enable */
222 {
223 GUSregb(TimerStatus2x8) |= 2; /* nonmaskable bit */
224 GUSregb(IRQStatReg2x6) |= 8; /* timer 2 irq pending */
225 GUSregw(TimerIRQs) += newtimerirqs;
226 requestedIRQs += newtimerirqs;
227 }
228 }
229 }
230 if (GUSregb(GUS4cReset) & 0x4) /* synth IRQ enable */
231 {
232 if (GUSregd(voicewavetableirq))
233 GUSregb(IRQStatReg2x6) |= 0x20;
234 if (GUSregd(voicevolrampirq))
235 GUSregb(IRQStatReg2x6) |= 0x40;
236 }
237 if ((!requestedIRQs) && GUSregb(IRQStatReg2x6))
238 requestedIRQs++;
239 if (GUSregb(IRQStatReg2x6))
240 GUSregw(BusyTimerIRQs) = GUS_irqrequest(state, state->gusirq, requestedIRQs);
241 }
242